Abstract: In view of the wide application of the belt dumping conveyor in the domestic mine，and in order to maximize dumping ability of the belt dumping conveyor，reduce the moving number of the orbit，and lower the cost of mine production，the largest bench height and the safety distance from the belt conveyor to the top line of the waste dump are analyzed.Based on the basic data，the seepage stability analysis，and the anti-sliding stability analysis，FLAC^3D is adopted to simulate the safety distance among the belt dumping conveyors for an open pit.According to the field condition，the potential caving forms at the bench slope of the waste dump under the equipment load are determined，and the safety distance model for the bench of the belt dumping conveyor is set up.The numerical simulation results indicate that the bench height is 75 m，and the safety distance among the conveyors is greater than 10 m.Combined with the experience，the maximum bench height and the safety distance are comprehensively determined，which has a guiding significance for the dumping and production by belt dumping conveyor in an Iron Mine.

Key words: Waste dump, Belt earth-disposal machine, Largest bench height, Safety distance, Lagrange finite-difference method